v3, 3 partsdelta-islands: avoid unused function messages

the macro generated code from delta-islands (using khash) triggers some unused function warnings in macOS, OpenBSD and some linux with a newer version of clang because of its use of static functions.

Changes from v2:
* Relay in the C code including git-compat-util as suggested by Jeff
* Commit message cleanup
* Make changes hdr-check clean

Changes from v1:
* Use MAYBE_UNUSED for all cases as suggested by Duy

Carlo Marcelo Arenas Belón (3):
  commit-slab: move MAYBE_UNUSED into git-compat-util
  khash: silence -Wunused-function in delta-islands from khash
  commit-slab: missing definitions and forward declarations (hdr-check)

 commit-slab-impl.h | 4 ++--
 commit-slab.h      | 2 ++
 git-compat-util.h  | 2 ++
 khash.h            | 2 +-
 4 files changed, 7 insertions(+), 3 deletions(-)

after 36da893114 ("config.mak.dev: enable -Wunused-function", 2018-10-18) it is expected to be used to prevent -Wunused-function warnings for code that was macro generated

Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 commit-slab-impl.h | 4 +---
 git-compat-util.h  | 2 ++
 2 files changed, 3 insertions(+), 3 deletions(-)

showing the following when compiled with latest clang (OpenBSD, Fedora and macOS):

delta-islands.c:23:1: warning: unused function 'kh_destroy_str'
      [-Wunused-function]
delta-islands.c:23:1: warning: unused function 'kh_clear_str'
      [-Wunused-function]
delta-islands.c:23:1: warning: unused function 'kh_del_str' [-Wunused-function]

Reported-by: René Scharfe <l.s.r@web.de>
Suggested-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 khash.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

On Thu, Oct 25, 2018 at 04:04:26AM -0700, Carlo Marcelo Arenas Belón wrote:

s/^s/S/ This applies to your other commit messages as well.

But more importantly, please be explicit about the compiler version that emits the warning, so others won't have to guess when stumbling upon this commit in a few months or years time.

struct commmit needs to be defined before commit-slab can generate working code, object_id should be at least known through a forward declaration

Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
---
 commit-slab-impl.h | 2 ++
 commit-slab.h      | 2 ++
 2 files changed, 4 insertions(+)

On 25/10/2018 12:04, Carlo Marcelo Arenas Belón wrote:

Hmm, sorry, I don't see how this patch has anything to do with the other two patches! ;-)

Also, I have a patch to fix up the 'commit-reach.h' header (it was part of my original series, just had to update the commit message), which adds these very #includes and forward declarations when _using_ the commit-slab.

I haven't tried applying your patches yet, which may answer my questions, so I am a little puzzled.

ATB, Ramsay Jones

On 25/10/2018 19:54, Ramsay Jones wrote:

So, having now applied your patches, I still don't see what this patch has to do with the others! I suppose it is dependent on the compiler/version? (the most up-to-date version of clang available to me is 5.0.1).

Yes, this will 'fix' the 'commit-reach.h' header (not surprising), but I prefer my patch. ;-)

Still puzzled.

ATB, Ramsay Jones

On Thu, Oct 25, 2018 at 2:09 PM Ramsay Jones <ramsay@ramsayjones.plus.com> wrote:

I apologize, I joined the list recently and so might had missed a reroll; the merged series in pu doesn't seem to include it and the error was around the code I changed, so wanted to make sure it would be addressed sooner rather than later.

eitherway, I agree with you my patch (or something better) would fit better in your topic branch than on mine and while I haven't seen your patch I am sure is most likely better.

this are the last lines of a `make hdr-check` in Fedora Rawhide, it should behave the same regardless of OS or compiler used IMHO

    HDR commit-reach.h
commit-reach.h:45:28: warning: ‘struct object_id’ declared inside
parameter list will not be visible outside of this definition or
declaration
 int ref_newer(const struct object_id *new_oid, const struct object_id
*old_oid);
                            ^~~~~~~~~
In file included from commit-slab.h:5,
                 from commit-reach.h:4:
commit-reach.h: In function ‘contains_cache_at_peek’:
commit-slab-impl.h:47:14: error: dereferencing pointer to incomplete
type ‘const struct commit’
  nth_slab = c->index / s->slab_size;    \
              ^~
commit-slab-impl.h:7:2: note: in expansion of macro ‘implement_commit_slab’
  implement_commit_slab(slabname, elemtype, static MAYBE_UNUSED)
  ^~~~~~~~~~~~~~~~~~~~~
commit-slab.h:49:2: note: in expansion of macro ‘implement_static_commit_slab’
  implement_static_commit_slab(slabname, elemtype)
  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
commit-reach.h:57:1: note: in expansion of macro ‘define_commit_slab’
 define_commit_slab(contains_cache, enum contains_result);
 ^~~~~~~~~~~~~~~~~~
commit-reach.h: At top level:
commit-reach.h:69:41: warning: ‘struct object_array’ declared inside
parameter list will not be visible outside of this definition or
declaration
 int can_all_from_reach_with_flag(struct object_array *from,
                                         ^~~~~~~~~~~~
make: *** [Makefile:2685: commit-reach.hco] Error 1

Carlo

On 26/10/2018 04:15, Carlo Arenas wrote:

Hmm, I don't know about that!

Since the original series has progressed, any additions will now result in a new set of patches, rather than a re-roll.

The original 'commit-reach.h' patch was not applied as part of the last series, since the commit message was felt to be lacking (well, it was actually non-existent!). ;-)

I have been making some additional changes to the 'hdr-check' target in the Makefile, but I haven't quite finished. I will send the other (non-Makefile) changes soon. [These patches will make the 'master' and 'next' branches 'hdr-check' clean for me].

ATB, Ramsay Jones